{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T14:17:57Z","timestamp":1785421077754,"version":"3.56.0"},"reference-count":31,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,7,11]],"date-time":"2026-07-11T00:00:00Z","timestamp":1783728000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004826","name":"Beijing Natural Science Foundation","doi-asserted-by":"publisher","award":["L232110"],"award-info":[{"award-number":["L232110"]}],"id":[{"id":"10.13039\/501100004826","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["82301078"],"award-info":[{"award-number":["82301078"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"award":["82301078"],"award-info":[{"award-number":["82301078"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Recurrence remains a significant challenge following the treatment of Severe Early Childhood Caries (S-ECC). This study aimed to identify candidate recurrence-related biomarkers for S-ECC and elucidate their potential pathogenic mechanisms. Through metagenomic sequencing of supragingival plaque from 32 children at one month post-treatment, we identified Leptotrichia hofstadii as one of the potential biomarkers for S-ECC recurrence (AUC = 0.8438 for the sequencing set and AUC = 0.75 for the validation set). In vitro dual-species biofilm assays using crystal violet staining and Confocal Laser Scanning Microscopy (CLSM) demonstrated that L. hofstadii promotes early-stage S. mutans colonization and extracellular polysaccharide (EPS) formation through contact-dependent synergistic interactions. Scanning electron microscopy revealed that L. hofstadii may function as a spatial scaffold within dual-species biofilm. Furthermore, this synergy significantly accelerates environmental acidification, leading to earlier attainment of the critical demineralization threshold (pH 5.5). At the transcriptional level, carbohydrate metabolism-related pathways were upregulated in dual-species biofilm, including starch and sucrose metabolism, PTS and ABC transporters. Additionally, the fruA gene, which degrades fructan in EPS was downregulated in the dual-species biofilm compared with S. mutans monoculture. These findings suggest that L. hofstadii facilitates a cariogenic microenvironment by enhancing the metabolic activity of S. mutans biofilms. Collectively, this study identifies L. hofstadii as a potential biomarker for S-ECC recurrence prediction and provides preliminary insights into possible interspecies mechanisms, offering valuable clues for future research into targeted preventive strategies.<\/jats:p>","DOI":"10.3390\/microorganisms14071513","type":"journal-article","created":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T07:28:27Z","timestamp":1783927707000},"page":"1513","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Identification of Leptotrichia hofstadii as a Post-Treatment Recurrence Biomarker in Severe Early Childhood Caries"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-0818-9576","authenticated-orcid":false,"given":"Yuchen","family":"Yin","sequence":"first","affiliation":[{"name":"Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, National Center of Stomatology\/National Clinical Research Center for Oral Diseases\/National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bingqian","family":"Zhao","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, National Center of Stomatology\/National Clinical Research Center for Oral Diseases\/National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruidi","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, National Center of Stomatology\/National Clinical Research Center for Oral Diseases\/National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Runkai","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, National Center of Stomatology\/National Clinical Research Center for Oral Diseases\/National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-4497-9564","authenticated-orcid":false,"given":"Jiahan","family":"Peng","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, National Center of Stomatology\/National Clinical Research Center for Oral Diseases\/National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bin","family":"Xia","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, National Center of Stomatology\/National Clinical Research Center for Oral Diseases\/National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2276-9286","authenticated-orcid":false,"given":"Jing","family":"Tian","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, National Center of Stomatology\/National Clinical Research Center for Oral Diseases\/National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,11]]},"reference":[{"key":"ref_1","unstructured":"World Health Organization (2022). 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